AQA Chapter 2.2

Question 0

What is a reducing sugar?

Answer 0

A reducing sugar is a sugar that can donate electrons to (or reduce) another chemical.

Question 1

What are monosaccharides?

Answer 1

Monosaccharides are sweet-tasting, soluble substances that have the general formula (CH2O)n, where n is any number from 3 to 7

Question 2

Are all monosaccharides reducing sugars?

Answer 2

Yes

Question 3

Are all disaccharides reducing sugars?

Answer 3

Only some disaccharides are reducing sugars

Question 4

How can you find out if a sugar is reducing?

Answer 4

You can used Benedict’s test

Question 5

How can you perform Benedict’s test?

Answer 5

Add the food sample being tested to a test tube (it should be in liquid form). Add an equal volume of Benedict’s reagent. Heat the mixture in a gently boiling water bath for 5 minutes.

Question 6

What is Benedict’s reagent exactly?

Answer 6

Benedict’s reagent is an alkaline solution of copper(ii) sulfate.

Question 8

After Benedict’s test has been conducted, what do the results mean?

Answer 8

Depending on the colour change, there are some reducing sugars in the sample. The colours are: CLEAR - GREEN - YELLOW - ORANGE - BRICK RED. (Scale: low concentration of reducing sugar to high)